1. Field of the Invention
The invention relates to forming ice cream and ice confections on plastic sticks and specifically relates to the one problem that has made it virtually impossible to use plastic sticks in forming ice confections. It is currently the industry standard to form such ice confections on sticks made of wood. Producers in the ice confection art have tried for years to employ plastic sticks but have had no success. As the speed of production of ice confections has increased, the time allowed for the stick to be inserted into the confection mold and to permit the temperature of the stick to equalize with the confection mold has decreased. The stresses resulting from the rapid thermal changes within the stick cause the stick to shatter, become unacceptably brittle, splinter, warp and become unusable.
Ice confection producers have been forced to use wooden sticks because sticks made of wood do not develop the thermal stresses when plunged from room temperature to the low temperature of the confection molds. Because wooden sticks are fibrous, the stresses within the wooden stick are relieved because the fibers can slip and adjust relative to one another to relieve the stresses of the thermal shock. As a matter of fact, wooden sticks become even more integral as the temperature is rapidly reduced because the fibers of wood not only slip relative to each other when under thermal stress, but they actually interlock and form a more rigid structure at low temperatures. Any consumer of ice confections which employ wooden sticks will note that the stick will become softer and the fibers will unlock as the confection is eaten and the stick is held in the mouth.
Further problems relating to the use of plastic sticks in the ice confection art relate to the smoothness of plastic surfaces, the lack of porosity of the plastic and the fact that the ice confection tends to slip from the plastic stick either during the confection forming process or during consumption of the confection. This problem is even more pronounced in the formation and consumption of ice cream having plastic sticks because of the low coefficient of friction of the plastic stick, which is oil based, and the ice cream, which is high in fat.
2. Description of the Prior Art
The present invention can be used with any conventional ice confection, ice cream or any other confection forming machine or method and simply includes the step in the process or apparatus in the machine for reducing the temperature of the plastic stick to a critically low temperature prior to and/or during the insertion into the confection mold. Conventionally, ice confection machines include rows of molds or confection cavities which are advanced through a brine tank or other refrigerating means, filling means for filling the molds with a confection substance which immediately begins to freeze and solidify, a stick insertion means for inserting individual (or plural) sticks into the confection which fills the molds at a point in time when the confection has solidified to the stage where it is solid enough to support the stick without appreciable relative movement. As the freezing process continues, the confection becomes firmly frozen and attached to the stick and continues to advance to an extraction means. Most often in today's high speed ice confection machines the confection is extracted from the mold by raising the temperature of the mold surrounding the frozen confection, gripping the stick and removing the frozen confection and stick by lateral movement between the stick gripping means and the mold. After the confection is frozen to the stick, it is removed from the mold and is passed to a wrapping and/or other storage means. When the confection does not have a uniform shape and thus cannot be withdrawn laterally it is obvious that an articulated mold may be used and the mold can be opened prior to lateral movement between the confection and the mold. Machines for making frozen confections may be in-line or circular wherein the confection molds move through the brine tank or other refrigeration means in a straight line, a curved line or circular path. Common machines for forming ice confections and inserting sticks into the confection during formation are included under the trademarks "VITALINE", "GRAM", "HOYER" and "STORMAX".
The prior art also shows the extreme difficulty of forming a solid bond between plastic sticks and confections of all kinds. Attempts have been made to increase the bond between sticks and the confection and include forming holes, shaping, and forming cavities or grooves in the stick.
The only significant reference found during a pre-examination search dealing with temperature control of sticks prior to or during formation of ice confections appears to be U.S. Pat. No. 2,957,435 [S. F. Anderson]. Anderson discloses chilling sticks to a temperature below the temperature of a semi-solid confection to ensure that the confection will sufficiently freeze to the stick to prevent the semi-solid bar from becoming dislodged from the stick during 16 subsequent handling of the bar by its stick handle. Col. 7, lines 5-11 of this reference refers to FIG. 6 and stick handle 30 which appears to be a common round stick made of twisted paper. There is no mention in this reference of plastic sticks or the problems of splintering, shattering, warping etc. associated with using plastic sticks or the problems of bonding the confection with plastic sticks. The present invention is directed to maintaining plastic confection sticks at critically low temperature prior to insertion into ice confections to prevent stick deterioration due to thermal shock and not to create bonding between sticks and semi-solid confections. In claim 1 of Anderson (435) it is seen that the sole purpose of cooling the stick (non-plastic) is to cause bonding of the semi-solid confection to the cold stick so that the confection may be transported through a freezing chamber while supported by the stick handle. As a matter of fact, the stick handle is not released by the stick inserter after insertion into the confection. Anderson discloses that the temperature of the stick is below the temperature of the confection. In the instant invention the temperature of the stick is controlled to different levels depending on the specific material of the stick and .the thermal gradient between the stick and the ice confection mold in modern high speed confection machines. Just cooling the sticks to a temperature below that of the confections to promote freezing of the confection to the cold stick is not sufficient to prevent deterioration of the stick. It is imperative to control the temperature to which the stick is cooled prior to insertion taking into consideration the specific material of the stick and the ultimate low temperature to which the plastic stick is subjected after insertion into the confection material.
U.S. Pat. No. 1,593,858 shows a popsicle or confection stick made of farinaceous material having circumferential or spiral grooves or any serrated or roughened surface. U.S. Pat. No. 2,929,340 shows inserting a knife into an ice cream body which melts a hole into the ice cream, withdrawing the knife and then inserting a stick into the hole and the melted ice cream then freezes about the stick. U.S. Pat. 2,469,589, 3,498,808, 3,663,717 and 3,748,778 show plastic materials used for forming confection sticks. U.S. Patents 1,929,906, 2,211,197, 2,821,481 and 5,042,860 show surface irregularities on sticks for retaining confections on sticks. U.S. Pat. Nos. 3,031,978, 3,407,755, 4,105,384, 4,507,070, 4,801,063, 4,976,597, 4,986,080 and United Kingdom Application 2,156,958 show methods and apparatus for inserting sticks in ice confections and withdrawing the stick supported ice confections after freezing. U.S. Pat. No. 2,052,574, 4,548,573 and 4,611,468 show inserting pegs and then removing the pegs prior to stick insertion in ice confection machines. U.S. Pat. No. 2,044,894 shows, in a batch process, sticking sticks into semi-solid confection material, freezing the material, heating the molds to release the outer surface of the ice confection and withdrawing the stick filled ice confection.